Petroleum Reduction Planning Tool Assumptions and Methodology

The Petroleum Reduction Planning Tool is a tool to help your vehicle fleet evaluate different methods for reducing petroleum consumption and greenhouse gas (GHG) emissions. For more information about the methodology, assumptions, and calculations used for each of the savings methods see the sections below:

Replace Vehicles

Replacing older vehicles with more fuel efficient and alternative fuel vehicles can reduce fuel costs and greenhouse gas emissions. See the explanations of the data and calculations below for replacing vehicles with new vehicles.

Substituting Fuel Type and Fuel Economy (with standard Powertrain)

The following values and variables are used when replacing a vehicle with a new vehicle that uses a new fuel type, has a new fuel economy (MPG), and a standard powertrain.

Data Entry
Value Variable Description
Number of Vehicles Veh Enter the number of vehicles that will use the alternative fuel.
Type of Vehicle --- Choose the vehicle type from the selections based on type and size.
Fuel Economy (MPG) MPG







MPG_new
Estimate the fuel economy for the vehicle(s). You may estimate the fuel economy (MPG) for each vehicle make and model using conventional fuel (gasoline or diesel) from your records. You can look up published fuel economy data for most vehicles available from fueleconomy.gov. Default values based on vehicle type are available in Table 2. Because the default values are based on national averages, they may vary significantly from your experience. It is strongly recommended that you use your own data when available.

Determine the published fuel economy of your replacement vehicle from fueleconomy.gov. If you do not know the type of vehicle you have you may use a default value, based on vehicle type in Table 2.
Miles traveled per year per vehicle VMT Estimate the number of miles that each vehicle will accumulate on average annually. If you do not have access to this data, default values are available in Table 4.
Powertrain --- Standard
Alt Fuel Used (%) Alt_fraction Estimate the amount of time the new vehicle will use an alternative fuel. This value will be 100 for a vehicle that uses a single dedicated type of fuel; this value could be significantly lower for a vehicle capable of running an alternative or conventional fuel (for example, E85 flex fuel vehicle).
Data Sources and Assumptions
Value Variable Description
GGE conversion factors Conventional_GGE_factor
Alt_GGE_factor_conv
Alt_GGE_factor
LHVfuel /LHVgasoline for the old vehicle
New vehicle using the conventional fuel
New vehicle using alternative fuel.

Values found in Table 1.
Greenhouse Gas Emissions Factor GHG_conventional
GHG_alt_conv
GHG_alt
Old vehicle using its conventional fuel
New vehicle using conventional fuel
New vehicle using alternative fuel.

Values found in Table 1.
Fuel Cost Fuel_cost_current
Fuel_cost_alt_new
Fuel_cost_alt
Fuel cost for old vehicle.
Fuel cost for new vehicle using conventional vehicle
Fuel cost for new vehicle using alternative fuel.

Note: If the old vehicle is gasoline and the new vehicle is an E85 flex fuel vehicle and operates a portion of the time on gasoline then Fuel_cost_current = Fuel_cost_alt_new.

Values found in Table 6.
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Calculations

  • Gallons of conventional fuel used
    Base_fuel_used = (Veh*VMT)/MPG

  • Gallons of conventional fuel used by new vehicle
    New_veh_used = (Veh*VMT)/MPG_new

  • Gallons of alternative fuel used by new vehicle
    Alt_fuel_used_new=New_veh_used*Alt_fraction

  • Gallons of gasoline equivalent of conventional fuel saved
    GGE_savings = (Base_fuel_used*Conventional_GGE_factor) - [(New_veh_used-Alt_fuel_used_new) + (Alt_fuel_used_new*(Alt_GGE_factor_conv/Alt_GGE_factor)*Blend_frac)]*Alt_GGE_factor_conv

  • Amount of Greenhouse Gases reduced by fuel substitution
    GHG_reduction = (Base_fuel_used*GHG_conventional*Conventional_GGE_factor) - [(New_veh_used*(1-Alt_fraction)*Alt_GGE_factor_conv)*GHG_alt_conv + (Alt_fuel_used_new*(Alt_GGE_factor_conv/Alt_GGE_factor)*Alt_GGE_factor*GHG_alt)]

  • Yearly fuel cost savings resulting from fuel and vehicle substitution
    Cost = (Base_fuel_used*Fuel_cost_current) - [(New_veh_used*(1-Alt_fraction)*Fuel_cost_alt_new + (Alt_Fuel_used_new*(Alt_GGE_factor_conv/Alt_GGE_factor)*Fuel_cost_alt)]


Example #1: Replace a midsize gasoline vehicle with a compact diesel using B20 50% of the time.

Veh = 1
MPG = 24.9 MPG
VMT (mi) = 12,427 mi
Alt_GGE_factor_conv = 1.124 GGE/gal diesel
GHG_conventional = 24.8 lb/GGE
GHG_alt_new = 21.7 lb/GGE
Fuel_cost_alt_new = 3.86 $/gal
Blend_frac = 0.8

Alt_fraction = 0.5
MPG_new = 36 MPG
Conventional_GGE_factor = 1.0 GGE/ gal gas
Alt_GGE_factor = 1.107 GGE/gal B20
GHG_Alt_conv = 25.4 lb/GGE
Fuel_cost_conventional = 3.46 $/gal
Fuel_cost_alt = 3.95 $/gal

Base_fuel_used = (1)(12,427)/(24.9) = 499.1 GGE gasoline
New_veh_used = (1)(12,427)/36 = 345.2 gallons conventional diesel fuel used by new vehicle
Alt_fuel_used_new = (345.2)(0.5) = 172.6 gallons of diesel
GGE_savings = (499.1)(1.0) - [(345.2-172.6)+(172.6)(1.124/1.107) (0.8)] (1.124) = 147.5 GGE saved
GHG_reduction = (499.1)(1.0)(24.8) - [(345.2)(1-0.5)(1.124)(25.4)+((172.6)(1.124/1.107)(1.107)(21.7)] = 3240.2 lbs GHG reduced

Cost = (499.1) (3.46)-[(345.2)(1-0.5)(3.86)+(172.6) (1.124/1.107)(3.95)] = 368.41 $/yr saved

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Substituting Fuel Type and Fuel Economy (with new Powertrain)

The following values and variables are used when replacing a vehicle with a new vehicle that uses a new fuel type, has a new fuel economy (MPG), and a new powertrain.

Data Entry
Value Variable Description
Number of Vehicles Veh Enter the number of vehicles that will use the alternative fuel (Veh).
Type of vehicle --- Choose the vehicle type from the selections based on type and size.
Fuel economy MPG
MPG_cs
MPG_cd

Estimate the fuel economy for the vehicle(s). You may estimate the fuel economy for each vehicle make and model using conventional fuel (gasoline or diesel) from your records. You can look up published fuel economy data for most vehicles available from fueleconomy.gov. Default values based on vehicle type are available in Table 2 (MPG). Because the default values are based on national averages, they may vary significantly from your experience. It is strongly recommended that you use your own data when available.

Determine the published fuel economy of your replacement vehicle from fueleconomy.gov.

Hybrid electric vehicles (HEVs) will have a single fuel economy number (in miles per gallon).

All-electric vehicles (EVs) will have a single fuel economy number (in kWh/100 mi).

Plug-in hybrid electric vehicles (PHEVs) will typically have two fuel economy numbers reported for the charge sustaining mode (in miles per gallon denoted by MPG_cs) and for the charge depleting mode (in kWh/100 mi denoted by MPG_cd).

If the fuel economy data for your replacement vehicle is unavailable you may use a default value, based on vehicle type from Table 3.

Note: The default values in Table 3 are modeled values based on NREL's Future Automotive Systems Technology Simulator (FASTSim). FASTSim predicts energy consumption of advanced powertrains over a wide range of vehicle classifications. Because the default values are based on modeled predictions, they may vary significantly; please refer to the notes at the end of this section.

It is strongly recommended that you use your own data or data from fueleconomy.gov data when available.

Miles traveled per year per vehicle VMT Estimate the number of miles that each vehicle will accumulate on average annually. If you do not have access to this data, default values are available in Table 4.
Alt fuel use (%) Alt_fraction Estimate the amount of time the new vehicle will use an alternative fuel. This value will be 100 for a vehicle that uses a single dedicated type of fuel; this value could be significantly lower for a vehicle capable of running an alternative or conventional fuel (for example, E85 flex fuel vehicle).
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Data Sources and Assumptions for Calculations
Value Variable Description
GGE conversion factors Conventional_GGE_factor
New_GGE_factor_conv_fuel
New_GGE_factor_alt_fuel
New_GGE_factor_elec
LHVfuel/LHVgasoline for the old vehicle
New vehicle using the conventional fuel
New vehicle using alternative fuel.
New vehicle using electricity.

Values found in Table 1.
Greenhouse Gas Emissions Factor GHG_conventional
GHG_new_conv_fuel
GHG_new_alt_fuel
GHG_new_elec
Old vehicle using its conventional fuel
New vehicle using conventional fuel
New vehicle using alternative fuel.
New vehicle using electricity.

Values found in Table 1.
Fuel Cost Fuel_cost_current
Fuel_cost_new_conv
Fuel_cost_new_alt
Fuel_cost_new_elec
Fuel cost for old vehicle.
Fuel cost for new vehicle using conventional vehicle
Fuel cost for new vehicle using alternative fuel.
Fuel cost for new vehicle using electricity.

Values found in Table 6.
Fleet Utility Factor FUF The Fleet Utility Factor is used from Table 3 based on the particular type of vehicle you chose. The utility factor is described in SAE J2481 and defines the fraction of driving in each of the fundamental modes, charge sustaining and charge depleting, based on the vehicles all electric or charge depleting range.

Calculations for Replacing a Vehicle with New Powertrain

  • Gallons of conventional fuel used by base vehicle
    Base_fuel_used = (Veh*VMT)/MPG

  • Gallons of primary fuel required for the new vehicle
    PHEV_combined_fuel_use = (Veh*VMT*(1 - FUF))/MPG_cs

  • Gallons of alternative fuel used by the new vehicle
    Alt_fuel_used_PHEV = PHEV_combined_fuel_use*Alt_fraction

  • GGE of electricity required by the new vehicle
    PHEV_elec_fuel_used = Veh*VMT*FUF*New_GGE_factor_elec*(MPG_cd/100)

  • Gallons of gasoline equivalent of conventional fuel saved
    GGE_savings = (Base_fuel_used*Conventional_GGE_factor) - [(PHEV_combined_fuel_use* (1 - Alt_fraction)* New_GGE_factor_conv_fuel) + (Alt_fuel_used_PHEV*(New_GGE_factor_conv_fuel/New_GGE_factor_alt_fuel) *New_GGE_factor_alt_fuel*Blend_frac)]

  • Amount of greenhouse gases reduced by fuel substitution
    GHG_reduction = (Base_fuel_used*Conventional_GGE_factor*GHG_conventional) - ((PHEV_combined_fuel_use*(1- Alt_fractiontion)*New_GGE_factor_conv_fuel)GHG_new_conv_fuel) - ((Alt_fuel_used_PHEV*(New_GGE_factor_conv_fuel/New_GGE_factor_alt_fue)*New_GGE_factor_alt_fuel)*GHG_new_alt_fuel) - (PHEV_elec_fuel_used* GHG_new_elec)

  • Yearly fuel cost savings resulting from fuel and vehicle substitution
    Cost = (Base_fuel_used *Fuel_cost_current) - [( PHEV_combined_fuel_use*(1 - Alt_fractiontion))*Fuel_cost_new_conv) - (Alt_fuel_used_PHEV*(New_GGE_factor_conv_fuel/New_GGE_factor_alt_fuel)*Fuel_cost_new_alt) - ((PHEV_elec_fuel_used/New_GGE_Factor_elec)*Fuel_cost_new_elec)]

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Example #2: Replace a midsize sedan (24.9 MPG) with a PHEV40 (36 MPG/36 kWh/100mi) powertrain, both use conventional gasoline.

Veh = 1
Alt_fraction = 0
MPG_cs = 36 MPG
FUF = 0.617
New_GGE_factor_conv_fuel = 1.0 GGE/gal gas
New GGE_factor_elec = 0.0296 GGE/kWh
GHG_new_conv_fuel= 24.8 lb/GGE
GHG_new_elec = 56.2 lb/GGE
Fuel_cost_new_conv = 3.46 $/gal
Fuel_cost_new_elec = 0.0983 $/kWh

VMT (mi) = 12,427 mi
MPG = 24.9 MPG
MPG_cd =36 kWh/100 mi
Conventional_GGE_factor = 1.0 GGE/gal gas
New_GGE_factor_alt_fuel = 0.727 GGE/gal E85
GHG_conventional = 24.8 lb/GGE
GHG_new_alt_fuel = 20.9 lb/GGE
Fuel_cost_current = 3.46 $/gal
Fuel_cost_new_alt = 3.14 $/gal
Blend_frac = 0.19

Base_fuel_use = (1)(12,427)/(24.9) = 499.1 Gallons of conventional fuel used by baseline vehicle
PHEV_combined_fuel_use = (1)(12,427)(1-0.617)/(36) = 132.2 Gallons of conventional fuel used by PHEV
Alt_fuel_used_PHEV = (132.6)(0) = 0 gallons of alternative fuel used
PHEV_elec_used = (1)(12,427)(0.617)(0.0296)(36/100) = 81.7 GGE of electricity used by PHEV
GGE_savings = (499.1)(1.0) - [(132.2)(1-0)(1.0) + (0)(1.0/0.727) (0.727) (0.19) ] = 366.9 GGE saved
GHG_reduction = (499.1)(1.0)(24.8) - (132.2)(1-0)(1.0)(24.8) - (0)(1.0/0.727) (0.727)(20.9) - (81.7)(56.2) = 4507.6 lbs GHG reduced

Cost = (499.1)(3.46)- [ (132.2)(1-0))(3.46) + (0)(1.0/0.727)(3.14) + (81.7/0.0296)*0.0983)] = 998.15 $/yr saved


Example #3: Replace a mid-size gasoline vehicle (24.9 MPG) with a PHEV40 (36 MPG/36 kWh/100mi). PHEV uses E85 50% of the time.

Veh = 1
Alt_fraction = 0.5
MPG_cs = 36 MPG
FUF = 0.617
New_GGE_factor_conv_fuel = 1.0 GGE/gal gas
New GGE_factor_elec = 0.0296 GGE/kWh
GHG_new_conv_fuel= 24.8 lb/GGE
GHG_new_elec = 55.8 lb/GGE
Fuel_cost_new_conv = 3.46 $/gal
Fuel_cost_new_elec = 0.0983 $/kWh

VMT (mi) = 12,427 mi
MPG = 24.9 MPG
MPG_cd =36 kWh/100 mi
Conventional_GGE_factor = 1.0 GGE/gal gas
New_GGE_factor_alt_fuel = 0.727 GGE/gal E85
GHG_conventional = 24.8 lb/GGE
GHG_new_alt_fuel = 20.9 lb/GGE
Fuel_cost_current = 3.46 $/gal
Fuel_cost_new_alt = 3.14 $/gal
Blend_frac = 0.19

Base_fuel_use = (1)(12,427)/(24.9) = 499.1 Gallons of conventional fuel used by baseline vehicle
PHEV_combined_fuel_use = (1)(12,427)(1-0.617)/(36)= 132.2 Gallons of conventional fuel used by PHEV
Alt_fuel_used_PHEV = 132.6)(0.5) = 66.1 Gallons of alternative fuel used by PHEV
PHEV_elec_used = (1)(12,427)(0.617)(0.0296)(36/100) = 81.7 GGE of electricity used by PHEV
GGE_savings = (499.1)(1.0) - (132.2)(1 - 0.5)(1.0) - (66.1)(1.0/0.727) (0.727) (0.19) = 384.9 GGE saved
GHG_reduction = (499.1)(24.8) - ((132.2)(1 - 0.5)(1.0))(24.8) - (66.1)(1.0/0.727)(0.727)(20.9) - (81.7)(56.2) = 4.765.4 lbs GHG reduced

Cost = ((499.1)(3.46) - ([132.2)(1-0.5)(3.46) + (66.1)(1.0/0.727)(3.14)+ (81.7/0.0296)*0.0983)] = 941.36 $/yr saved

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Example #4: Replace 1 midsize gasoline sedan (24.9 MPG) with 1 EV (36 kWh/100mi).

Veh = 1
Alt_fraction = 1.0
MPG_cs = 0 MPG
FUF = 1.0
New_GGE_factor_conv_fuel = 0.0 GGE/gal gas
New GGE_factor_elec = 0.0296 GGE/kWh
GHG_new_conv_fuel= 0 lb/GGE
GHG_new_elec = 55.8 lb/GGE
Fuel_cost_new_conv = 0.0 $/gal
Fuel_cost_new_elec = 0.0983 $/kWh

VMT (mi) = 12,427 mi
MPG = 24.9 MPG
MPG_cd =36 kWh/100 mi
Conventional_GGE_factor = 1.0 GGE/gal gas
New_GGE_factor_alt_fuel = 0.0 GGE/gal E85
GHG_conventional = 24.8 lb/GGE
GHG_new_alt_fuel = 0.0 lb/GGE
Fuel_cost_current = 3.46 $/gal
Fuel_cost_new_alt = 0.0 $/gal
Blend_frac = 0.0

Base_fuel_use = (1)(12,427)/(24.9) = 499.1 GGE conventional fuel used by baseline vehicle
PHEV_combined_fuel_use = (1)(12,427)(1-1.0)/(36)= 0.0 gallons conventional fuel used by PHEV
Alt_fuel_used_PHEV = (0)(1.0) = 0.0 gallons of alternative fuel used
PHEV_elec_used = (1)(12,427)(1.0)(0.0296)(36/100) = 132.4 GGE of electricity used by PHEV
GGE_savings = (499.1)(1.0) - (0.0)(1 - 1.0)(1.0) - (0.0)(1.0/0.0)(0.0)(0.0) = 499.1 GGE saved
GHG_reduction = (499.1)(1.0)(24.8) - ((0.0)(1-1.0)(1.0))(24.8) - (0.0)(1.0/0.0)(0.0)(20.9) - (132.4)(56.2) = 4,936.8 lbs GHG reduced

Cost = (499.1)(3.46) - ([132.2)(1-0.5)(3.46) + (66.1)(1.0/0.727)(3.14)+ (81.7/0.0296)*0.0983)] = 941.36 $/yr saved


Example #5: Replace 1 midsize gasoline sedan (24.9 MPG) with 1 compact HEV (42 MPG).

Veh = 1
Alt_fraction = 0.0
MPG_cs = 42 MPG
FUF = 0.0
New_GGE_factor_conv_fuel = 1.0 GGE/gal gas
New GGE_factor_elec = 0.0 GGE/kWh
GHG_new_conv_fuel= 24.8 lb/GGE
GHG_new_elec = 0.0 lb/GGE
Fuel_cost_new_conv = 3.46 $/gal
Fuel_cost_new_elec = 0.0 $/kWh

VMT (mi) = 12,427 mi
MPG = 24.9 MPG
MPG_cd =0.0 kWh/100 mi
Conventional_GGE_factor = 1.0 GGE/gal gas
New_GGE_factor_alt_fuel = 0.0 GGE/gal E85
GHG_conventional = 24.8 lb/GGE
GHG_new_alt_fuel = 0.0 lb/GGE
Fuel_cost_current = 3.46 $/gal
Fuel_cost_new_alt = 0.0 $/gal
Blend_frac = 0.0

Base_fuel_use = (1)(12,427)/(24.9) = 499.1 Gallons conventional fuel used by baseline vehicle
PHEV_combined_fuel_use = (1)(12,427)(1- 0.0)/(42)= 295.9 Gallons conventional fuel used by PHEV
Alt_fuel_used_PHEV = (295.9)(0) = 0.0 Gallons of alternative fuel used
PHEV_elec_used = (1)(12,427)(0)(0.0)(0/100) = 0.0 GGE of electricity used by PHEV
GGE_savings = (499.1)(1.0) - (295.9)(1 - 0.0)(1.0) - (0.0)(1.0/0.0)(0.0)(0.0) = 203.2 GGE saved
GHG_reduction = (499.1)(1.0)(24.8) - ((295.9)(1-1.0)(1.0))(24.8) - (0.0)(1.0/0.0)(0.0)(0.0) - (0)(0) = 5039.4 lbs GHG reduced

Cost = (499.1)(3.46)- [(295.9)(1-0.0)(3.46) + (0)(1.0/0.0)(0.0)+ (0.0/0.0)*0.0)] = 703.07 $/yr saved

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Use Alternative Fuel in Existing Vehicles

Several alternative fuels may be used to displace petroleum. The following section outlines the methodology for calculating petroleum reduction using alternative fuels in existing vehicles.

Data Entry
Value Variable Description
Number of Vehicles Veh Enter the number of vehicles that will use the alternative fuel (Veh).
Type of vehicle --- Choose the vehicle type from the selections based on type and size.
Fuel economy MPG Estimate the fuel economy for the vehicle(s). You may estimate the fuel economy for each vehicle make and model using conventional fuel (gasoline or diesel) from your records. You can look up published fuel economy data for most vehicles available from fueleconomy.gov. Default values based on vehicle type are available in Table 2. Because the default values are based on national averages, they may vary significantly from your experience. It is strongly recommended that you use your own data when available.
Miles traveled per year per vehicle VMT Estimate the number of miles that each vehicle will accumulate on average annually. If you do not have access to this data, default values are available in Table 4.
Alt fuel use (%) Alt_fraction Estimate the amount of time the vehicle will use the alternative fuel. This value will be 100 for a vehicle that uses a single dedicated type of fuel. This value could be significantly lower for a vehicle capable of running an alternative or conventional fuel (e.g. E85 flex fuel vehicles).
Data Sources and Assumptions
Value Variable Description
GGE conversion factors Conventional_GGE_factor LHVfuel/LHVgasoline for the old vehicle

Values found in Table 1.
Greenhouse Gas Emissions Factor GHG_conventional
GHG_alt_conv
GHG_alt
Vehicle using its conventional fuel
Vehicle using conventional fuel
Vehicle using alternative fuel

Values found in Table 1.
Fuel Cost Fuel_cost_current
Fuel_cost_alt_new
Fuel_cost_alt
Fuel cost for old vehicle.
Fuel cost for new vehicle using conventional vehicle

Fuel cost for new vehicle using alternative fuel.

Note: If the old vehicle is gasoline and the new vehicle is an E85 flex fuel vehicle and operates a portion of the time on gasoline then Fuel_cost_current = Fuel_cost_alt_new.

Values found in Table 6.
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Calculations

  • Gallons of baseline fuel used
    Base_fuel_used = (Veh*VMT)/MPG

  • Gallons of Alternative fuel used in alternative fueled vehicle
    Alt_fuel_used =Base_fuel_used*Alt_fraction

  • Gallons of base fuel used in alternative fueled vehicle
    Fuel_used =Base_fuel_used*(1-Alt_fraction)

  • Gallons of gasoline equivalent reduced
    GGE_saved = Alt_fuel_used*Alt_GGE_factor_conv) - [(Alt_fuel_used*(Alt_GGE_factor_conv/Alt_GGE_factor)* (Alt_GGE_factor_conv)*Blend_frac)]*Alt_GGE_factor_conv

  • Amount of Greenhouse Gases reduced by fuel substitution
    GHG_reduction = (Base_fuel_used*Conventional_GGE_factor*GHG_conventional) - [(Fuel_used*Alt_GGE_factor_conv*GHG_alt_conv) + (Alt_fuel_used*(Alt_GGE_factor_conv/Alt_GGE_factor)*Alt_GGE_factor*GHG_alt)]

  • Amount of cost savings realized by fuel substitution
    Cost = (Base_fuel_used*Fuel_cost_current) - [(fuel_used*Fuel_cost_alt_new) + (Alt_fuel_used*(Alt_GGE_factor_conv/Alt_GGE_factor)*fuel_cost_alt)]


Example #1: Use E85 in 3 midsize sedans 50% of the time.

Veh = 3
Alt_fraction = 0.5
Conventional_GGE_factor = 1.0 GGE/gal gas
Alt_GGE_factor_conv = 1.0 GGE/gal gas
GHG_Conventional = 24.8 lb/GGE
Fuel_cost_current = 3.46 $/gal
Fuel_cost_alt_new = 3.46 $/gal

VMT (mi) = 12,427 mi
MPG = 28 MPG
Alt_GGE_factor = 0.727 GGE/gal E85
GHG_alt_conv = 24.8 lb/GGE
GHG_Alt_conv = 25.4 lb/GGE
Fuel_cost_conventional = 3.46 $/gal
Fuel_cost_alt = 3.14 $/gal

Base_fuel_used = (3) (12,427)/28 = 1331.5 GGE (gallons of gasoline)
Alt_fuel_used = (1331.5) (0.5) = 665.7 gallons of alternative fuel
Fuel_used = (1331.5)(1-0.5) = 665.7 gallons of conventional fuel used
GGE_saved = (665.7)(1.0) - [(665.7)(1/0.727)(0.19) (1.0)] = 491.7 GGE saved
GHG_reduction = (1331.1) (1.0) (24.8) - [(665.7) (1.0) (24.8) + (665.7) (1.0/0.727) (0.727) (20.9)] = 2588.9 Lbs GHG

Cost = (1331.1) (3.46) - [(665.7) (3.46) + (665.7) (1/0.727) (3.14)] = -572.95 $/yr (additional cost)


Example #2: Use B20 in 4 heavy-duty trucks 30% of the time.

Veh = 4
Alt_fraction = 0.3
Conventional_GGE_factor = 1.124 GGE/gal diesel
Alt_GGE_factor = 1.107 GGE/gal B20
GHG_alt = 21.7 lb/GGE
Fuel_cost_current = 3.86 $/gal
Fuel_cost_alt_conv = 3.86 $/gal

VMT (mi) = 7,760 mi
MPG = 5.8 MPG
Alt_GGE_factor_conv = 1.124 GGE/gal diesel
GHG_Conventional = 25.4 lb/GGE
GHG_alt_conv = 25.4 lb/GGE
Fuel_cost_alt = 3.95 $/gal
Blend_frac = 0.8

Base_fuel_used = (4)(7,760)/5.8 = 5351.7 gallons of diesel
Alt_fuel_used = (5351.7) (0.3) = 1605.5 gallons of alternative fuel
Fuel_used = (5351.7)(1-0.7) = 3746.2 gallons of conventional fuel used
GGE_saved = (1605.5) (1.124) - [(1605.5)(1.124/1.107)(0.8) (1.124)] = 338.7 GGE saved
GHG_reduction = (5351.7) (1.124) (25.4) - [(3746.2) (1.124) (25.4) + (1605.5) (1.124/1.107) (1.107) (21.7)] = 6,676.9 Lbs GHG

Cost = (5351.7) (3.86) - [(3746.2) (3.86) + (1605.5) (1.124/1.107) (3.95)] = -241.11 $/yr (additional cost)

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Idle Time Reduction

Idle time reduction refers to times when a vehicle is turned off instead of left idling. Idle time reduction strategies can be as simple as stopping the vehicles engine at stop lights or while parked during a delivery. Idle reduction strategies may also encompass methodologies such as truck stop electrification, where the driver plugs his vehicle in to power necessary systems rather than idling, or using on-board auxiliary power units. The following section outlines the methodology for calculating petroleum reduction using idle reduction.

Data Entry
Value Variable Description
Number of Vehicles Veh Enter the number of vehicles that will use the alternative fuel (Veh).
Type of vehicle --- Choose the vehicle type from the selections based on type and size.
Idling time (hrs/day) OIT

NIT
Estimate the time the vehicle(s) spend idling in hours each day.

Estimate the new idle time limits in hours each day.
Days per year Days Estimate the number of days per year that the targeted vehicle(s) operate. This may be determined from your records or you may use a default value from Table 5. However, since default values are based on nationwide statistics, they may vary considerably from your data. It is strongly recommended that you use your own data when possible.
Data Sources and Assumptions
Value Variable Description
GGE conversion factors Conventional_GGE_factor LHVfuel/LHVgasoline for the old vehicle

Values found in Table 1.
Greenhouse Gas Emissions Factor GHG_conventional Vehicle using its conventional fuel

Values found in Table 1.
Fuel Cost Fuel_cost_current Fuel cost for vehicle.

Values found in Table 6.

Calculations

  • Gallons of conventional fuel saved
    GGE_saved =Veh*(OIT - NIT)*Conventional_GGE_factor*days*Idle_use

  • Amount of Greenhouse Gases reduced
    GHG_reduction = GGE_saved*GHG_conventional

  • Amount of cost savings realized
    Cost = (GGE_save/Conventional_GGE_factor)*Fuel_cost_current


Example #1: Use E85 in 3 midsize sedans 50% of the time.

Conventional_GGE_factor = 1.124 GGE/gal diesel
GHG_conventional = 25.4 lb/GGE
Veh = 4
NIT = 3.5 hr/day

Days = 250
Idle_use = 1 gal/hr
OIT = 4 hrs/day
Fuel_cost_current = $3.86

GGE_saved = (4) (4-3.5) (250) (1.0) (1.124) = 562.0 GGE
GHG_reduced = 562.0 (25.4) = 14,274.8 Lbs GHG reduced
Cost = (562.0/1.124) (3.86) = $1,930.00

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Reduce Mileage

Vehicle miles traveled (VMT) reduction refers to substituting conventional travel with a mode of transportation that reduces petroleum consumption. This includes methods such as biking, walking, eliminating trips or increasing the efficiency of existing vehicles by using mass transit or developing advanced fleet strategies, such as route planning. The following section outlines the methodology for calculating petroleum reduction reduced mileage.

Data Entry
Value Variable Description
Number of Vehicles Veh Enter the number of vehicles that employ the fuel economy improvements.
Type of vehicle --- Choose the vehicle type from the selections based on type and size.
Fuel Economy MPG Estimate the fuel economy for the vehicle(s). You may estimate the fuel economy for each vehicle make and model using conventional fuel (gasoline or diesel) from your records. You can look up published fuel economy data for most vehicles available from fueleconomy.gov. Default values based on vehicle type are available in Table 2. Because the default values are based on national averages, they may vary significantly from your experience. It is strongly recommended that you use your own data when available.
Miles traveled per year per vehicle VMT



VMT_new
Estimate the number of miles that each vehicle accumulates on average annually. If you do not have access to this data, default values are available in Table 4.

Determine the new annual vehicle miles traveled you expect with your planned reduction.
Data Sources and Assumptions
Value Variable Description
GGE conversion factors Conventional_GGE_factor LHVfuel/LHVgasoline for the vehicle(s)

Values found in Table 1.
Greenhouse Gas Emissions Factor GHG_conventional Vehicle using its conventional fuel

Values found in Table 1.
Fuel Cost Fuel_cost_current Fuel cost for vehicle.

Values found in Table 6.

Calculations

  • Gallons of gasoline equivalent of conventional fuel saved
    GGE_saved = (Veh*(VMT - VMT_new)*Conventional_GGE_factor)/MPG

  • Amount of Greenhouse Gases reduced fuel substitution
    GHG_reduction = GGE_saved*GHG_conventional

  • Amount of cost savings realized by fuel substitution
    Cost = (GGE_saved/Conventional_GGE_factor)*Fuel_cost_current


Example #1: Reduce miles traveled in 5 midsize sedans with average fuel economy of 24.9 MPG.

MPG = 24.9 MPG
Veh = 5
VMT_new = 13,000 mi/yr
Conventional_GGE_factor = 1.0 GGE/gallon

GHG_conventional = 24.8 lb/GGE
VMT (mi) = 15,000 mi/yr
Fuel_cost_current = 3.46 $/gal

GGE_saved = (5) (15,000-13,000) (1.0)/ (24.9) = 401.6 GGE saved
GHG_reduction = 401.6(24.8) = 9959.7 Lbs GHG reduced
Cost = (401.6/1) (3.46) = 1,389.54 $/yr saved

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Drive Efficiently

There exist a number of methods to improve the fuel economy of a vehicle or fleet of vehicles. Technologies in this category include such things as changing driver behavior (for example, reducing fast starts) and improved maintenance (for example, proper tire inflation).

Data Entry
Value Variable Description
Number of Vehicles Veh Enter the number of vehicles that employ the fuel economy improvements.
Type of vehicle --- Choose the vehicle type from the selections based on type and size.
Fuel Economy MPG Estimate the fuel economy for the vehicle(s). You may estimate the fuel economy for each vehicle make and model using conventional fuel (gasoline or diesel) from your records. You can look up published fuel economy data for most vehicles available from fueleconomy.gov. Default values based on vehicle type are available in Table 2. Because the default values are based on national averages, they may vary significantly from your experience. It is strongly recommended that you use your own data when available.
Miles traveled per year per vehicle VMT



VMT_new
Estimate the number of miles that each vehicle will accumulate on average annually. If you do not have access to this data, default values are available in Table 4.
Fuel Economy Improvement (%) MPG_improvement Estimate the percentage improvement in fuel economy you expect from fuel economy improvements such as driver behavior changes, proper maintenance of vehicles, etc.
Data Sources and Assumptions
Value Variable Description
GGE conversion factors Conventional_GGE_factor LHVfuel/LHVgasoline for the old vehicle

Values found in Table 1.
Greenhouse Gas Emissions Factor GHG_conventional Vehicle using its conventional fuel

Values found in Table 1.
Fuel Cost Fuel_cost_current Fuel cost for vehicle.

Values found in Table 6.

Calculations

  • Target fuel economy
    MPG_new = (1+MPG_improvement)*MPG

  • Gasoline gallons equivalent of conventional fuel saved
    GGE_saved = (Veh*VMT*Conventional_GGE_factor)*(1/MPG - 1/MPG_new)

  • Amount of Greenhouse Gases reduced with fuel substitution
    GHG_reduction = GGE_saved*GHG_conventional

  • Amount of cost savings realized by switching fuels
    Cost = GGE_saved*Fuel_cost_current


Example #1: Improve efficiency in 1 midsize sedan with an average fuel economy of 22 MPG. Fuel economy improvement 15%.

MPG = 22 MPG
Veh = 1
Fuel_cost_current = $3.46/gal

GHG_conventional = 24.8 lb/GGE
VMT (mi) = 10,000 mi/yr
Conventional_GGE_factor = 1.0 GGE/gal

FE_new = (1+0.15) (22) = 25.3 MPG
GGE_saved = (1) (10,000) (1.0)*(1/22 - 1/25.3) = 59.3 GGE
GGE_savings = (59.3) (1.0) = 59.3 GGE saved
GHG_reduction = (59.3) (24.8) = 1,470.6 Lbs GHG reduced
Cost = (59.3) (3.46) = 204.18 $/yr saved

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Data Values and Conversion Factors

The following tables contain the values used for variables in the sections above.

Table 1. Basic Conversion Factors
Fuel GGE Conversion Factors
LHVfuel/LHVgasoline
(GGE/Unit of fuel)
GHG Conversion Factors (lb/GGE) Blend Fraction (%) Source
Gasoline 1.0 24.8 1.0 GREET1-2011
E85 0.727 20.9 0.19
Natural Gas (CNG) 1.0 22.4 1.0
Liquified Natural Gas (LNG) 0.649 22.3 1.0
Propane (LPG) 0.737 22.5 1.0
Diesel 1.124 25.4 1.0
B5 1.119 24.5 0.95
B10 1.115 23.6 0.9
B20 1.107 21.7 0.8
B100 1.038 3.1 1.0
Electricity 0.0296 56.2 1.0
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Table 2. Fuel Economy (MPG) (All values in miles per gallon)
Parameter Value Source
Gasoline Cars
Mini-compact 26.0 AEO 2011 (Table 70) 2011 new car values adjusted by degradation factor (Report No. EPA-420-R-10-023 November 2010, Table A4)
Sub-compact 26.9
Compact 25.7
Midsize 24.9
Large 24.1
Diesel Cars
Compact 31.6 AEO 2011 (Table 70) 2011 new car values adjusted by degradation factor (Report No. EPA-420-R-10-023 November 2010, Table A4)
Midsize 30.7
Gasoline Light-duty Trucks
Small pickup 19.3 AEO 2011 (Table 70) 2011 new car values adjusted by degradation factor (Report No. EPA-420-R-10-023 November 2010, Table A4)
Large pickup 17.7
Small van 21.4
Large van 21.2
Small sport utility vehicle 22.2
Large sport utility vehicle 22.0
Diesel Light-duty Trucks
Large pickup 22.0 AEO 2011 (Table 70) 2011 new car values adjusted by degradation factor (Report No. EPA-420-R-10-023 November 2010, Table A4)
Large van 26.3
Small SUV 26.9
Large SUV 21.8
Gasoline Medium-duty Trucks
MD truck 10,000-14,000 lbs 7.6 TEDB 30th Edition, Davis et al. 2011, Table 5.4; class 3 adjusted for spark ignition and LHV gasoline
Diesel Medium/Heavy-duty Trucks
MD truck 10,000-14,000 lbs 10.5 TEDB 30th Edition,Davis et al. 2011, Table 5.4
MD truck 14,001-26,000 lbs 7.3
Heavy-duty truck > 26,000 6.0
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Table 3. Advanced Powertrain Fuel Economies and Fleet Utility Factors
Vehicle MPG_cs
Charge Sustaining Fuel Economy (MPG)
MPG_cd
Charge Depleting Fuel Economy (kWh/mi)
FUF
Fleet Utility Factor*
Source
Mini-Compact Cars
Mini-compact HEV 45 N/A 0.00 NREL's Future Automotive Systems Technology Simulator (FASTSim**)
Mini-compact PHEV10 45 26.6 0.23
Mini-compact PHEV20 44 26.2 0.4
Mini-compact PHEV40 43 31.9 0.62
Mini-compact BEV75 N/A 36.1 1.00
Sub-Compact Cars
Sub-compact HEV 42 N/A 0.00 FASTSim**
Sub-compact PHEV10 42 22.8 0.23
Sub-compact PHEV20 42 29.7 0.4
Sub-compact PHEV40 41 34.7 0.62
Sub-compact BEV75 N/A 38.5 1.00
Compact Cars
Compact HEV 42 N/A 0.00 FASTSim**
Compact PHEV10 42 30.8 0.23
Compact PHEV20 41 29.7 0.4
Compact PHEV40 40 36.5 0.62
Compact BEV75 N/A 38.9 1.00
Midsize Cars
Midsize HEV 39 N/A 0.00 FASTSim**
Midsize PHEV10 39 31.1 0.23
Midsize PHEV20 39 31.8 0.4
Midsize PHEV40 37 37.6 0.62
Midsize BEV75 N/A 41.6 1.00
Large Cars
Large HEV 36 N/A 0.00 FASTSim**
Large PHEV10 36 35.3 0.23
Large PHEV20 36 36.1 0.4
Large PHEV40 34 40.6 0.62
Large BEV75 N/A 44.5 1.00
Small Trucks
Small Truck HEV 31 N/A 0.00 FASTSim**
Small Truck PHEV10 31 31.8 0.23
Small Truck PHEV20 31 37.7 0.4
Small Truck PHEV40 30 46.9 0.62
Small Truck BEV75 N/A 52.4 1.00
Large Trucks
Large Truck HEV 26 N/A 0.00 FASTSim**
Large Truck PHEV10 26 36.5 0.23
Large Truck PHEV20 26 15.0 0.4
Large Truck PHEV40 25 55.1 0.62
Large Truck BEV75 N/A 62.1 1.00
Small Vans
Small Van HEV 32 N/A 0.00 FASTSim**
Small Van PHEV10 32 31.8 0.23
Small Van PHEV20 31 40.3 0.4
Small Van PHEV40 30 46.5 0.62
Small Van BEV75 N/A 50.4 1.00
Large Vans
Large Van HEV 25 N/A 0.00 FASTSim**
Large Van PHEV10 25 40.9 0.23
Large Van PHEV20 24 49.0 0.4
Large Van PHEV40 23 60.8 0.62
Large Van BEV75 N/A 68.1 1.00
Small SUV
Small SUV HEV 33 N/A 0.00 FASTSim**
Small SUV PHEV10 33 31.6 0.23
Small SUV PHEV20 33 35.8 0.4
Small SUV PHEV40 32 44.8 0.62
Small SUV BEV75 N/A 50.2 1.00
Large SUV
Large SUV HEV 25 N/A 0.00 FASTSim**
Large SUV PHEV10 25 40.9 0.23
Large SUV PHEV20 24 53.1 0.4
Large SUV PHEV40 23 64.5 0.62
Large SUV BEV75 N/A 28.0 1.00

* Fleet Utility Factor, SAE J2841_201009, Utility Factor Definitions for Plug-In Hybrid Electric Vehicles Using 2001 U.S. DOT National Household Travel Survey Data.
** NREL's Future Automotive Systems Technology Simulator (FASTSim) is an advanced vehicle modeling tool used to predict energy consumption of conventional, hybrid, and all-electric powertrains over a broad range of vehicle classifications. FASTSim is a lumped-parameter model that simulates component operation and interaction subject to vehicle time/speed traces. Modeled components include: engine, electric motor/controller, traction battery, fuel tank, and wheels. Primary FASTSim outputs include city/highway fuel economy test results, acceleration capabilities, and vehicle purchase and operation costs. Additional details concerning FASTSim can be found in the following publications:

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Table 4. VMT Default Values
Parameter Value Source
Car 11,919 Transportation Energy Data Book, 30th Edition, Davis et al. 2011.
Table 4.1
LD truck 11,555 Table 4.2
MD truck < 14,000 lbs 14,094 Table 5.4
MD truck 14,000-26,000 lbs 12,964 Table 5.4, weighted avg. of class 4, 5, 6
HD truck 45,133 Table 5.4, weighted avg. of class 7, 8
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Table 5. Default Values for Idle Fuel Consumption
Parameter Value Source
HD Diesel 0.8gal diesel/hour/vehicle Estimation of Fuel Use by Idling Commercial Trucks, Gaines et al. 2006
MD Diesel 0.6 gal diesel/hour/vehicle
LDV Diesel 0.17 gal gal diesel/hour/vehicle
LDV Gasoline 0.23 gal gal gasoline/hour/vehicle
Average idling time per year per vehicle (OIT) 1830 hours/year
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Table 6. Basic Fuel Pricing
Fuel Fuel Price
($/unit of fuel)
Unit Source
Biodiesel (B5) 2.41 Gallon Source for all fuels except electricity: Alternative Fuel Price Report, updated quarterly.

Source for electricity pricing: US Energy Information administration
Biodiesel (B10) 2.41 Gallon
Biodiesel (B20) 2.49 Gallon
Biodiesel (B100) 3.09 Gallon
Electricity 0.12 kWh
Natural Gas (CNG) 2.15 Gasoline Gallon Equivalent
Propane (Liquefied Petroleum Gas) 2.83 Gallon
Gasoline 2.38 Gallon
Diesel 2.55 Gallon
Table 7. Gross Vehicle Weight (GVW)
Parameter Value Source
Light-duty (LD) <= 10,000 lbs TEDB 30th Edition, Davis et al. 2011
Medium-duty (MD) 10,001-26,000 lbs
Heavy-duty (HD) > 26,001 lbs
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